The present invention relates to a head carriage apparatus, and more particularly, to a head carriage apparatus where a magnetic head is in moving contact with a recording medium according to a displacement of an upper arm.
In general, magnetic disk apparatus that use flexible magnetic disks as the recording medium have a head carriage apparatus. This head carriage apparatus is provided internal to a magnetic disk apparatus, and has a configuration where there is movement in the direction of the diameter of a magnetic disk. Accordingly, the head carriage apparatus can move the magnetic head to an arbitrary position on the magnetic disk.
FIG. 1 shows a conventional head carriage apparatus. As is shown in the figure, a head carriage apparatus 1 has a configuration comprising a head carriage main unit 2 and an upper arm 3. The upper arm 3 is connected with the head carriage main unit 2 by a leaf spring 4 to form a single unit. In addition, the numeral 5 denotes a head load spring, which urges the upper arm 3 in the clockwise direction shown in the diagram.
Furthermore, to the side portion of the upper arm 3 is formed a protrusion 3a and to the lower portion of the protrusion 3a is formed a bale 6. This bale 6 is formed as one portion of a disk holder, and accordingly, rises and falls in accordance with the insertion and removal of a magnetic disk 7 (housed in a disk cartridge). Magnetic heads 8,9 are provided so as to oppose the lower portion of the upper arm 3 and the upper portion of the head carriage main unit 2. Moreover, the numeral 10 in the figure is a chassis, and the numeral 11 is a cover that covers the upper portion of the chassis 10. The head carriage apparatus 1 having the configuration described above, is configured so that the upper arm 3 rotationally displaces when the bale 6 rises. More specifically, when the magnetic disk 7 is mounted and dismounted, the rising of the bale 6 causes the protrusion 3a to lift, so that the upper arm 3 rotates in the counterclockwise direction.
When a conventional head carriage apparatus 1 has the upper arm 3 rotationally displaced as described above, the upper arm 3 is in the state where it forms a relatively large angle .theta.1 with respect to the horizontal direction (with the upper arm 3 having the inclined state shown in FIG. 1).
In a conventional head carriage apparatus 1 having the configuration described above, the upper arm 3 is in the state where it is inclined at the relatively large angle .theta.1 with respect to the horizontal direction when the magnetic disk 7 is mounted and dismounted. Accordingly, the magnetic head 8 mounted to the upper arm 3 is also in an inclined state accompanying this movement.
In addition, the angle of inclination of the upper arm 3 must be such that the lowest position of the inclined magnetic head 8 is at a position higher than the position at which the magnetic disk 7 is inserted and removed. If it not set in this manner, then the magnetic disk 7 will strike the magnetic head 8 when the magnetic disk 7 is inserted and removed.
Accordingly, in the conventional head carriage apparatus 1, it is necessary to have a large angle of inclination for the upper arm 3 and because of this, it is necessary to have a large space for the rotation of the upper arm 3. This serves to increase the size of the magnetic disk 7 and to create a problem in making it more compact. In the example shown in FIG. 1, it is necessary to have a space with the height indicated by the arrow L inside the magnetic disk 7 so that the upper arm 3 can be rotated.